Thread-controlling mechanism for sewing machines



G. s. GATCHELL.

Dec. 19, 1922.

I THREAD CONTROLLING MECHANISM FOR SEWING MACHINES.

3 SHEETS SHEET 1 FILED MAR. 10. 1921.

WITNESSES;

3 SHEE IS SHEET 2.

Dec. 19, 1922.

G. S. GATCHELL. THREAD CONTROLLING MECHANISM r05 SEWING MACHINES. FILEDMAR. 10. I921.

WITNESSES:

Dec. 19, 1922. 1,439,468. G. s. GATCHELL.

THREAD CONTROLUNG MECHANISM FOR SEWING MACHINES.

FILED MAR. 10.1921. s SHEETS-SHED 3.

VIIIIIIIII'IIII WITNESSES: 4 INVENTO mm N 7 Patented Dec. 19, 1922.

UNITED STATES 1,439,468 PATENT OFFICE.

GEORGE S. GATCHELL, OF ROSELLE PARK, NEW JERSEY, ASSIGNOR TO THE SINGERMANUFACTURING COMPANY, OF ELIZABETH, NEW JERSEY, A. CORPORATION OF NEWJERSEY.

"f' A THREAD-CONTROLLING MECHANISM :E/OR SEWING M ACHINES.

Application filed March 10, 1921. /Serial No. 451,188.

T 0 all whom it may concern:

Be it known that I, GEORGE S. GATCHELL, a citizen of'the United States,residing at Roselle lark, in the county of Union and State of NewJersey, have invented certain new and useful Improvements inThreadontrolling Mechanisms for Sewing Machines. of which the followingis a specification, reference being had therein to the accompanyingdrawings. v

This in'iprovement relates to thread-controlling mechanism for sewingmachines, more particularly of the chain-stitch type and has for anobject to provide a compact thread controlling mechanism of simplifiedconstruction which in a chain-stitch machine will accomplish thedelivery and the taking up of the looper-thread, to and from the looper,in the proper amounts and at the proper times during the stitch-formingcycle to insure the uniform and correct for mation of stitches with aminimum amount of the relatively expensive upper or needlethread and amaximum amount of under or looper-thread of poor quality.

A further object of the invention is to provide a looper-threadcontrolling mecha nism particularly adapted for installation in machineshaving the sewing point close to the standard or vertical member of thebracket-arm.

Still further. the invention has for an object to provide alooper-thread take-up which will permit the use of relatively weaklooper-thread of poor quality and which will not tend to wind up thelooper-thread, even though the latter should break while the machine isin operation. a

In the embodiment of the invention illustrated the objects of theinvention are attained by mounting upon the oscillating looper-carrier athread-guiding fork between the tines of which oscillates a thread cammounted upon a vibratory looper-actuating lever. The cam is so shapedas' to cooperate with the oscillatory thread-guiding fork to take threadfrom and pay it out to the looper as required for the correct formationof stitches. The looper-carrier also supports a pair oflooper-thread'nipper-springs which are depressed into contact relationwith an adjustable stationary nipper-closing stop by the lateral motionof the loopercarrier in carrying the looper from one side of the needle'to the other at the end of the loop-seizing stroke of the looper. Thenipper-springs are thus held closed during the loop-shedding stroke ofthe looper. A suitable pull-oti' device is preferably provided for thelooper-thread at the supply side of the thread-nipper and its functionis to provide slack thread to be drawn through the open nipper by theadvancing looper, so that the looper may go forward on a loose threadand thus avoid undue shortening of the previous looper looplying on theunder side of the work.

In the accompanying drawings, Fig. l. is a side elevation of the bed ofa sewing machine embodying the improvement, the needle being at its hihest point and the looper fully forward. Fig. 2 is a plan View of thesame. Fig. 3 is a perspective view of the looper-carrier. Fig. 4 is aperspective View of the oscillating support for the looper-carrier. Fig.5 is a vertical sectional view through the bracket-arm standardtransversely of the main-shaft. Fig 6 is .a view of the take-up elementsat the period of the cycle when the needle is fully down and the looperretracted. Fig. 7 is a similar view with the looper advancing to seize aneedle-gloop, and Fig. 8 shows the looper retracting and the needleentering the triangle 'formed by the looper-thread looper-blade andprevious needle-loop.

In the specific embodiment of the invention illustrated. the sewingmachine frame comprises a bed 1. bracket-arm standard 2 and head 3 inwhich the needleand presserbars are mounted; said bars carryingrespectively, the needle 4 and presser-foot 5. The presser-foot 5cooperates with a suitable four-motion feed-dog 6 which operates throughthe usual apertured throat-plate 7 let into the cloth-plate 8. It willbe noted that, in the machine illustrated. the line of seam-formationrepresented by the. position of the needle 4, is close to the standard2,

so that space between the sewing point and the standard 2 for workingparts beneath the cloth-plate 8 is at a premium.

Cooperating with the needle 4, below the throat-plate T is the looper 9which is mounted on the looper-carrier 10 formed with an apertured andsplit hub 11 which is journa led for rocking movement upon the lateralpin 12 secured in the split socket 12' block 16 on the eccentric 1?fixed to the main-shaft 18. This eccentric and the described connectionstherewith operate to im part the usual sidewise or so-calledneedleavoiding movements to the looper J.

The looper derives its loop-seizing or endwise movements through a trainof connections including the link 19 joining the ball 20 on thelooper-carrier with a similar ball at the upper end of the arm 21 of abellcrank lever fulcrumed at 22 to the bed 1. T he other arm 23 of thebellcrank-lever is connected by the pitman 24 to one arm 25 of an upperbellcrank-lever fixed to and having for its fulcrum support the usualneedle-actuating shaft 26. The other arm 27 of the upper bellcrank-leveris connected by the pitman 28 to the crank 29 on the main-shaft 18.

To avoid the danger of winding up the. looper-thread, the presentlooper-thread take-up is made oscillatory in character, rather thanrotary. Also it is of a character such that it may be compactlyinstalled in a short arm and bed sewing machine, where there would notbe room for a rotary or other known looper-thread take-up. Mounted uponthe looper-carrier is one element 30 of a take-up comprising coactingtl'iread-engaging devices, preferably the coacting thread-guide. andthread-cam type. In the embodiment of the invention illustrated themember 30 is the thread-guide member and is in the form of a fork, thetines of which are apertured at 31 to receive the looper-thread 1 Thethread fork 30 is fixed relatively to the looper 9 and moves with thelatter both endwise and sidewise.

Cooperating with the oscillating threadguiding fork 30 is theoscillating threadcam 32 having the active edge which passes between thetines of the fork 30. The cam 32 is mounted on an arm 34, which isadjustably secured by means of a slotand-screw connection 35 to arecessed seat 35, Fig. 5, in the arm 21 of the bellcranklever 21, 23.

The support 13 for the looper-carrier 10 is formed with a hub extension36 on which is mounted the pair of thread-nipper springs 37 extendingparallel -to the rockshaft 14. v The opening and closing action of thesprings 37 is controlled by a stopscrew 38 which is adjustably threadedinto the bed 1.

A free supply of slack loo .)er-thread may be assured if desired byproviding a pull-off device comprising a pair of spaced arms 31) mountedon the pitman28 and projecting forwardly through a slot 10 in the frontside of the standard 2. Bisecting the slot 40 is a cast-oti' plate a1.Mounted on the standard 2 at the sides of the path of motion of thepull-off arms 39 are the thread-guides As the crank 29 revolves, thefree ends of the arms 39 are moved in an egg-shaped path, as shown inFig. 5, and seize the looper-thread between the guides 12, lifting saidthread until the latter is cast oli' of the ends of said arms by theoutwardly and upwardly inclined edge '43 of the cast-off plate 11. Thepull-oif action is timed to occur when the nipper-springs 37 are closed,thereby providing a bight of slack thread which is drawn through theDipper-springs by the looper or take-up, when said springs are open. Theamount of thread pulled off may be varied by adjusting the threadguides-12 and the cast-off plate vertically; adjustable screw and slotconnections 42 being provided for this purpose.

The operation of the take-up elements 30, 32, is substantially astoll0ws:.'-Starting in the position shown in Fig. (3 with the needledown and the looper retracted; as the looper advances to seize aneedle-loop, the rising thread-eyes 31 and forwardly tilting edge 33 ofthe cam 32 operate to absorb thread and take up the thread in front ofthe eye of the looper, thereby preventing buckling of the looper-thread.As soonv as the looper beak is well into the needle-loop, or a littlepast the position shown in Fig. 7, the thread betweenthe guide-eyes 31slips over the central hump of the cam-edge 33 andslack is afforded sothat the looper may go forward to the end of its stroke, on a slackthread. \Vherrthe looper reaches the end of its loop-seizing stroke,Fig. 1, substan tially all the slack looper-thread has been absorbed bythe looper. As the looper moves'sidewise in the early stage ofitsretracting stroke, the nipper springs 37 are closed and thedescending thread-eyes 31 coact with the cam-edge 33, to take up thethread given up by the retracting looper, as shown in Fig. 8. After theneedle has entered the loopcrloop. the thread between the guideeyes 31slips downwardly over the central hump of the cam-edge 33 and slacklooper-thread is afforded to permit the needle-loop to be readily andfully tightened so as to draw the requisite amount of slacklooper-thread into the stitch being formed. By the means described,correct formation of the stitches is assured without straining thelooper-thread: the needle-loops being fully drawn up and only the tipsthereof being visible at the under side of the work. The use of amaximum amount of looperthread and a minimum amount of needlethread isthus assured.

The invention is not to be understood as limited to the preciseconstruction and arrangement of parts'shown and described as. variousmodifications within the scope and spirit of the invention willdoubtless be suggested to those skilled in the art from the foregoingdisclosure.

Having thus set forth the nature of the invention, what I claim hereinis 1. Looper-thread controlling mechanism for sewing machines comprising.a threadcarrying looper having the usual endwise and sidewisemovements, and a looper-thread take-up including coactingthread-engaging .devices one of which is fixed relative to said looper.

2. Looper-thread controlling mechanism for sewing machines comprising athreadcarrying looper having the usual endwise and sidewise movements,and a looper-thread take-up including coacting thread-guide andthread-cam elements, one of which is fixed relative to said looper.

3. In a sewing machine, in combination, a reciprocating needle, athread-carrying looper, a thread-guide moving with said looper and anoscillating cam cooperating with said threadguide to control thelooper-thread.

4. In a sewing machine, in combination, a reciprocating needle, athread-carrying looper, a looper-carrier, an oscillating lever andconnections for imparting loop-seizing and shedding movements to theloopercarrier, and cooperating thread-cam and threadguide elementsmounted on said looper-carrier and oscillating lever.

5. In a sewing machine, in combination, a

reciprocating needle, a thread-carrying looper, coacting looper-threadguide and cam elements mounted to oscillate about independent fulcra,and means for oscillating 'said thread-guide and cam elements in timewith the needle and looper.

6. In a sewing machine, in combination, a looper, a looper-carrier, athread-guiding fork mounted on the looper-carrier and an oscillatingthread-cam operating between the tines of the thread-fork to control thelooperthread.

7. Looper-thread controlling mechanism for sewing machines comprising, alooper, means including a looper-carrier for imparting the usual loopseizing and sidewise movements to the looper, and coacting thread-guideand thread cam elements vfor the looper thread, one of said elementsbeing mounted on the looper-carrier.

8. Looper-thread controlling mechanism for sewing machines comprising, alooper, means including a looper-carrier for imparting the usualloop-seizing and sidewise movements to the looper, a thread-guidemounted on the looper-carrier, and a thread cam cooperating with saidguide to control the looper-thread.

9. Looper-thread controlling mechanism for sewing machines comprising, alooper, means including a looper-carrier for imparting the usual loopseizing and sidewise movements to the looper, a thread-guide mounted onthe looper-carrier, and an oscillatory thread-cam cooperating with saidguide to control the looper-thread.

10. Thread controlling mechanism for sewing machines comprising coactingthreaduide and thread-cam elements mounted to oscillate about spacedaxes, and means for oscillating said elements synchronously;

ll. Thread-controlling mechanism for sewing machines comprising coactingthreadguide and thread-cam elements mounted to oscillate" about spacedaxes, and means for oscillating said elements synchronously andsimultaneously in the same angular direction about their respectiveaxes.

12. Thread-controlling mechanism for sewing machines having, incombination, a pair of pivoted arms, a link connection between saidarms, means for oscillating said arms, a thread-guide mounted on one ofsaid arms, and a thread-cam mouinted on the other of said arms incooperative relation with said thread-guide.

13. In a sewing machine, in combination, a thread-carrying looper, alooper-carrier, a rocking support for the looper-carrier, athread-nipper mounted on said rocking sup port. and a looper-threadtakeup including coacting thread-cam and thread-guide elements one ofwhich is mounted on and derives its movement from the looper-carrier.

1&.' In a sewing machine, in combination, a looper, a looper-carrier, arocking support for the looper-carrier, a pair of tl'n'ead-nippersprings mounted on said support in substantial parallelism with the axisof rocking motion of the latter, and a stop coacting with said springs.

In testimony whereof, I have signed my name to this specification.

GEORGE S. GATCHELL.

